1. Field of the Invention
The invention relates to a motor vehicle head rest having a center window and adapted to be adjusted by the user to extend at the desired height and with the desired slant relative to the back rest of the motor vehicle seat provided with the head rest.
2. Description of the Prior Art
Various head rests with a center window for motor vehicles are known which include a support frame embedded in a cushion body and two mounting rods adapted to be attached at one pair of corresponding ends to the back rest of a motor vehicle seat, said support frame having two hollow side struts receiving the other corresponding ends of the mounting rods and being adapted to be shifted along the mounting rods and/or to be pivoted with respect thereto.
With one such head rest, the two hollow side struts of the support frame are each in the form of a tube in order to run on its respective mounting rod end, and the cushion body is provided with two elastic clamping members for the one and respectively the other mounting rod, especially with two rubber sleeves, which each clamp on the respective mounting rod adjacent to the opening therefor in the respective side strut of the support frame. This head rest can be adjusted in height, but not with respect to its slant angle. An example of this type of head rest is disclosed by German utility model No. 7,623,536.
Another type of head rest is known wherein the two hollow side struts of the support frame each have a side chamber at the end adjacent to the respective mounting rod, and the two mounting rod ends received in the side struts are each provided with an end section bent at a right angle and clamped in a slotted plastic bushing arranged in the chamber of the side strut associated with the mounting rod end and screwed to the support frame. The two side strut chambers are placed opposite to each other between the center opening of the support frame and its end adjacent to the mounting rods, as well as the two mounting rod end sections, about which the support frame may be pivoted in relation to the mounting rods until inner abutment surfaces of its side struts engage the mounting rods on the one or the other side of the same. This head rest may only be adjusted as to its angle of slant and cannot be adjusted in height. An example of this type of head rest is disclosed by German utility model No. 7,722,401.
Lastly, still another type of head rest is known wherein the two hollow side struts of the support frame have two sliding plastic sleeves disposed therein which extend for at least half the height of the support frame, run on the ends of the two mounting rods extending in the side struts and are adapted to be pivoted in the side struts about a common pivot axis extending adjacent and parallel to a lower longitudinal strut of the support frame parallel thereto. At the ends adjacent to this longitudinal strut and from which the sliding sleeves extend towards an upper longitudinal strut of the support frame or in the opposite direction to the mounting rod openings of the side struts thereof, the sliding sleeves are each provided with a perpendicular lateral stud or projection. The two mutually opposite studs defining the common pivot axis, each are clamped in a slotted plastic bushing arranged in a chamber formed in the adjacent end of the lower longitudinal strut of the support frame and screwed to the latter. The two projections extend on the same side beside the plane defined by the corresponding mounting rod ends and are passed by a common bearing pin which also passes through the two side struts of the support frame and defines the pivot axis. The sliding sleeves are each locked by detent means onto the mounting rod end sliding therein, and for this purpose they are each provided with a resilient catch element cooperating with catch notches of the associated mounting rod end. The side struts of the support frame each have internal abutment surfaces for the respective sliding sleeve which diverge away from the said pivot axis. These head rests are adapted to be adjusted in height and inclination and are disclosed by German Pat. No. 3,021,122 and German patent application No. 3,200,321.